Half a million severely immunocompromised patients should be getting a third dose of a COVID-19 vaccine, including those on chemotherapy, high-dose corticosteroids, B-cell-depleting therapies and long-term dialysis, ATAGI has recommended.

It’s the first time ATAGI has advised anything beyond a two-dose course, although potential boosters for doctors and other health staff are still under review, with more advice expected to arrive by the end of the month.

“The third dose is intended to maximise the level of immune response to as close as possible to the general population,” ATAGI said in a statement issued on Friday.

Immunocompromised patients had accounted for 44% of breakthrough infections leading to hospitalisation in one US study, the advisory group noted.